OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.

This is in response to your letter dated October 6, 2003, to the Occupational Safety and Health Administration (OSHA). We have paraphrased your questions as follows:

Question (1):Scenario: A 20-inch x 20-inch mechanical chase (chute) extends from the basement to the third floor within a residential structure. On each floor it is formed by wall studs that are 16 inches on center (14½-inch gap between studs). Do the spaces between the studs or the floor holes of the chase require fall protection (such as a guardrail system or cover) under §1926.501?

"Wall openings" Each employee working on, at, above, or near wall openings (including those with chutes attached) where the outside bottom edge of the wall opening is 6 feet (1.8 m) or more above lower levels and the inside bottom edge of the wall opening is less than 39 inches (1.0 m) above the walking/working surface, shall be protected from falling by the use of a guardrail system, a safety net system, or a personal fall arrest system.

An "opening" [in a wall/partition] is defined in §1926.500(b) as:

a gap or void 30 inches (76 cm) or more high and 18 inches (48 cm) or more wide, in a wall or partition, through which employees can fall to a lower level.

A "hole" [in a walking/working surface] is defined in §1926.500(b) as:

a gap or void 2 inches (5.1 cm) or more in its least dimension, in a floor, roof, or other walking/working surface.

The floor holes within the chase would pose a fall hazard to workers on each floor unless exposure to the holes is eliminated or fall protection is provided.1As you state in your letter, the 14½-inch gaps between the studs are smaller than those needed to meet the definition of an "opening." As these gaps in the stud walls are not considered wall openings, the stud walls prevent the workers from unintentionally falling into the holes in the chase.

In most cases, therefore, the studs suffice to prevent exposure of the workers to these holes.

However, there are situations where it is reasonably foreseeable that workers will intentionally step through the framed (but unsheathed) wall studs that surround the hole. For example, in some cases, because of the small size of the hole and its location, employees may step through a chase as a short cut to the opposite side. Another example would be where lighting conditions are so poor that employees may not realize that there is a hole there. In these types of situations, further action would be required -- either the floor hole must be covered in accordance with §1926.502(i) (requirements for covers), or a guardrail installed, or some means implemented of effectively communicating to the employees that they are not to step through the chase (such as through an effectively communicated and enforced rule prohibiting the practice coupled with warning signs or warning tape around the chase).

Also, if employees have work that would involve their being within the chase, under §1926.501(b)(4), the holes must be covered (or personal fall protection used).

Question (2):Scenario:An open stairwell 40 inches wide is surrounded on three sides by interior stud walls, within a residential structure (the fourth side has a guardrail across it). The walls are unsheathed and the studs are 16 inches on-center (14½-inch gap between studs). Do the spaces between the studs require fall protection (such as a guardrail system or cover over the stairwell) under §1926.501?

Answer:

The open stairwell is a hole that would pose a fall hazard to those on the floors around it unless exposure to it is eliminated or fall protection is provided. As discussed above, the 14½-inch gaps between the studs are smaller than those needed to meet the definition of an "opening." As these gaps in the stud walls are not considered wall openings, the stud walls prevent the workers from being intentionally exposed to the hazard of the open stairwell. Also, stairwells are normally large enough so that it is not reasonably foreseeable that an employee would purposefully step through the stud walls. Therefore, the employer normally is not required to provide a guardrail across the stud walls under §1926.501(b)(14).2

If you need additional information, please contact us by fax (202-693-1689) at: U.S. Department of Labor, OSHA, Office of Construction Standards and Guidance. You can also contact us by mail at U.S. Department of Labor, OSHA, Office of Construction Standards and Guidance, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.

Sincerely,

Russell B. Swanson, Director
Directorate of Construction

1 §1926.501(b)(4)(i) states:

Each employee on walking/working surfaces shall be protected from falling through holes (including skylights) more than 6 feet above lower levels, by personal fall arrest systems, covers, or guardrail systems erected around such holes.

§1926.501(b)(4)(ii) states:

Each employee on a walking/working surface shall be protected from tripping in or stepping into or through holes (including skylights) by covers. [

back to text]2 In addition, in this scenario, where there is a guardrail across the one open side of the stairwell and stud walls (16 inches on center) around the other three sides, there is normally no requirement to cover the stairwell. [back to text]

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